Where to buy (or order) GPS unit in Chiang Mai?

I need a GPS for solo off-road riding. I ride around the Chiang Mai area mostly but I want to start heading up towards Mae Hong Son for long off-road tours. I want a handheld - something like the Garmin 60csx or a lesser model. These are selling for 6,000 baht in America.

I've only found one shop in town (at Panthip plaza) but the prices seemed out of control (12,000+ for Garmin 60csx). Where do you guys shop?